The present invention relates to a new and improved construction of apparatus for measuring the color of glass, particularly broken glass.
In its more specific aspects, the present invention particulaly relates to a new and improved construction of apparatus for measuring the color of glass, particularly broken glass pieces and which apparatus includes means for simultaneousy measuring the transmission of the glass pieces in different spectral regions. The glass pieces are passed along a conveying path which extends between a light source and a light sensor or sensor head containing a plural number of optical filters and associated photoelectric detectors.
A sorting apparatus such as known, for example, from U.S. Pat. No. 3,980,180, granted Sep. 14, 1976, includes a belt conveyor receiving single glass particles in depressions which are aligned with apertures provided in the belt conveyor. The belt conveyor passes a sensing station containing light sources on one side of the belt conveyor and light detectors located on the opposite side of the belt conveyor so that light transmitted by the glass particles is detected. The light sources and the light detectors are selected so as to respectively emit and sense light of a narrow band width in a manner such that the intensity of the light transmitted by the glass particles is indicative of the color of the glass particles. The sensing station is followed in the conveying direction of the belt conveyor by a separating station which is provided with corresponding sensing means and compressed air nozzles producing an air jet for blowing away into a collecting container any glass particles having a predetermined color. A number of such sensing and separating stations may be arranged in series along the belt conveyor such that each of the combinations is responsive to a different color; also, a single sensing station may be provided to operate on a number of series-arranged separating stations.
The known installation is rather cumbersome and requires a comparatively large number of elements which tends to increase the danger of malfunction and/or failures.